A sophisticated drug tunnel that spanned the border between San Diego and Tijuana, Mexico, was packed with more than eight tons of marijuana and hundreds of pounds cocaine, federal officials said today.

The tunnel, shut down on Wednesday, links warehouses in San Diego's Otay Mesa industrial park and Tijuana. "It is equipped with electricity, ventilation and a rail system," ICE spokeswoman Lauren Mack told ABCNews.com.

Inside the recently completed tunnel, authorities discovered more than eight tons of pot as well as 325 pounds of cocaine.

It was the latest drug tunnel to be shut down in the area in recent years, but it marked "the first time cocaine has been recovered in connection with a local drug tunnel," Mack said.

Authorities said that three suspects are now in custody facing federal charges.

The underground smuggling route was discovered by San Diego Tunnel Task Force, which consists of investigators from ICE, Homeland Security, Customs, Border Patrol and the Drug Enforcement Administration.

Mexican news organizations published photos that show a deep, well-built tunnel near Tijuana's main airport.

More than 75 tunnels have been discovered along the U.S.-Mexico border since 2008, designed largely to smuggle marijuana to the United States. San Diego is popular with tunnelers because its clay-like soil is easy to dig. Also, the U.S. side of the border is home to many warehouses.